Question #5015

a school photocopier has a 95% chance of working on any particular day. Draw a tree diagram showing the possibiltiies for the working or otherwise of the photocopier over 2 consecutive days. Hence, determine the likelihood that it will be working on at least one of these days.

Expert's answer

Here is current diagram:

first day& second day

& & work(0.95)

/

work(0.95)& &

& / \

& /& & no work(0.05)

/

\& work(0.95)

& \& /

& no work(0.05)

& \

& no work(0.05)

So, the probability that a school photocopier will be working on at least one of two consecutive days is

P = 0.95*0.95 = 0.95² = 0,9025.

first day& second day

& & work(0.95)

/

work(0.95)& &

& / \

& /& & no work(0.05)

/

\& work(0.95)

& \& /

& no work(0.05)

& \

& no work(0.05)

So, the probability that a school photocopier will be working on at least one of two consecutive days is

P = 0.95*0.95 = 0.95² = 0,9025.

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